import AsyncStorage from '@react-native-async-storage/async-storage'
import { Linking, Platform } from 'react-native'
import { apiRequest, getConfig, getUserId, _registerUserInfoHandler } from '@xuqm/rn-common'
import { getAppVersionCode, getAppVersionName, _devSetAppVersion } from './NativeVersion'
import { md5 } from './md5'

// ─── Types (public) ────────────────────────────────────────────────────────────

/** 插件注册（版本号由 SDK 自动获取，不需要 App 传入） */
export interface PluginRegistration {
  moduleId: string
}

/** @deprecated 使用 PluginRegistration（移除 version 字段） */
export interface PluginMeta extends PluginRegistration {
  version?: string
}

export interface AppUpdateInfo {
  needsUpdate: boolean
  versionName?: string
  versionCode?: number
  downloadUrl?: string
  changeLog?: string
  forceUpdate?: boolean
  appStoreUrl?: string
  marketUrl?: string
  requiresLogin?: boolean
  alreadyDownloaded?: boolean
  apkHash?: string | null
}

export interface PluginUpdateInfo {
  needsUpdate: boolean
  latestVersion: string
  currentVersion: string
  downloadUrl: string
  md5: string
  minCommonVersion: string
  note: string
  forceUpdate?: boolean
  changeLog?: string
}

export type UpdateDownloadProgress = {
  bytesDownloaded: number
  totalBytes: number
  /** 0-100 */
  percent: number
}

export type { CachedRnBundle }
interface CachedRnBundle {
  moduleId: string
  version: string
  md5: string
  downloadedAt: string
  source: string
}

// ─── Internal state ────────────────────────────────────────────────────────────

const _pluginRegistry = new Set<string>()

// ─── Update check cache ────────────────────────────────────────────────────────

const UPDATE_APP_CACHE_KEY = 'xuqm_update_app_cache'
const UPDATE_PLUGIN_CACHE_KEY_PREFIX = 'xuqm_update_plugin_cache_'
const UPDATE_CACHE_TTL_MS = 30 * 60 * 1000 // 30 minutes

async function _readUpdateCache<T>(key: string): Promise<T | null> {
  try {
    const raw = await AsyncStorage.getItem(key)
    if (!raw) return null
    const cached = JSON.parse(raw) as { ts: number; data: T }
    if (Date.now() - cached.ts < UPDATE_CACHE_TTL_MS) return cached.data
    return null
  } catch {
    return null
  }
}

async function _writeUpdateCache<T>(key: string, data: T): Promise<void> {
  try {
    await AsyncStorage.setItem(key, JSON.stringify({ ts: Date.now(), data }))
  } catch {
    // cache write failure is non-fatal
  }
}

let _writeBundleCallback: ((moduleId: string, source: string) => Promise<void>) | null = null
let _reloadBundleCallback: ((moduleId: string) => Promise<void>) | null = null

function bundleCacheKey(moduleId: string) {
  return `@xuqm:bundle:${moduleId}`
}

async function _getCachedVersion(moduleId: string): Promise<string> {
  const raw = await AsyncStorage.getItem(bundleCacheKey(moduleId)).catch(() => null)
  if (!raw) return '0.0.0'
  const cached = JSON.parse(raw) as CachedRnBundle
  return cached.version ?? '0.0.0'
}

function normalizeDownloadUrl(rawUrl?: string): string | undefined {
  if (!rawUrl) return rawUrl
  if (rawUrl.includes('/api/v1/updates/api/v1/rn/files/')) {
    return rawUrl.replace('/api/v1/updates/api/v1/rn/files/', '/api/v1/rn/files/')
  }
  if (rawUrl.includes('/files/apk/')) {
    try {
      const url = new URL(rawUrl)
      if (url.pathname.startsWith('/files/apk/')) {
        return `${url.origin}/api/v1/updates${url.pathname}${url.search}`
      }
    } catch {}
  }
  return rawUrl
}

async function _downloadText(url: string, onProgress?: (p: number) => void): Promise<string> {
  const response = await fetch(url)
  if (!response.ok) throw new Error(`[UpdateSDK] Download failed: ${response.status}`)
  if (!onProgress) return response.text()
  const contentLength = Number(response.headers.get('Content-Length') ?? '0')
  const reader = response.body?.getReader()
  if (!reader) return response.text()
  const chunks: Uint8Array[] = []
  let received = 0
  for (;;) {
    const { done, value } = await reader.read()
    if (done) break
    chunks.push(value)
    received += value.length
    if (contentLength > 0) onProgress(received / contentLength)
  }
  const decoder = new TextDecoder()
  return chunks.map(c => decoder.decode(c, { stream: true })).join('') + decoder.decode()
}

async function _downloadBinary(url: string, onProgress?: (p: number) => void): Promise<ArrayBuffer> {
  const response = await fetch(url)
  if (!response.ok) throw new Error(`[UpdateSDK] Download failed: ${response.status}`)
  if (!onProgress) return response.arrayBuffer()
  const contentLength = Number(response.headers.get('Content-Length') ?? '0')
  const reader = response.body?.getReader()
  if (!reader) return response.arrayBuffer()
  const chunks: Uint8Array[] = []
  let received = 0
  for (;;) {
    const { done, value } = await reader.read()
    if (done) break
    chunks.push(value)
    received += value.length
    if (contentLength > 0) onProgress(received / contentLength)
  }
  const totalLength = chunks.reduce((acc, c) => acc + c.length, 0)
  const combined = new Uint8Array(totalLength)
  let offset = 0
  for (const chunk of chunks) {
    combined.set(chunk, offset)
    offset += chunk.length
  }
  return combined.buffer
}

// ─── 订阅 setUserInfo（userId 用于定向更新） ──────────────────────────────────

_registerUserInfoHandler(() => {
  // updatePlugin 检查更新时会实时调用 getUserId()，此处无需额外操作
})

// ─── UpdateSDK ────────────────────────────────────────────────────────────────

export const UpdateSDK = {

  // ── 宿主注入（插件化写入/重载能力）──────────────────────────────────────────

  /**
   * 注入 bundle 写入和重载回调。
   * 宿主在初始化时调用（如 src/core/updater.ts），注入 BundleRuntime 能力。
   *
   * @example
   * UpdateSDK.setBundleCallbacks({
   *   writeBundle: writeBundleFile,
   *   reloadBundle: loadBundle,
   * })
   */
  setBundleCallbacks(callbacks: {
    writeBundle: (moduleId: string, source: string) => Promise<void>
    reloadBundle: (moduleId: string) => Promise<void>
  }): void {
    _writeBundleCallback = callbacks.writeBundle
    _reloadBundleCallback = callbacks.reloadBundle
  },

  // ── 插件注册 ──────────────────────────────────────────────────────────────

  /**
   * 批量注册插件。版本号由 SDK 自动从本地缓存获取，不需要 App 传入。
   *
   * @example
   * UpdateSDK.registerPlugins([{ moduleId: 'buz1' }, { moduleId: 'buz2' }])
   */
  registerPlugins(plugins: PluginRegistration[]): void {
    for (const p of plugins) {
      _pluginRegistry.add(p.moduleId)
    }
  },

  /**
   * 注册单个插件（向后兼容；version 字段已废弃，SDK 自动获取）。
   */
  registerPlugin(meta: PluginRegistration): void {
    _pluginRegistry.add(meta.moduleId)
  },

  getRegisteredPlugins(): string[] {
    return Array.from(_pluginRegistry)
  },

  // ── App 整包更新 ──────────────────────────────────────────────────────────

  async checkAppUpdate(bypassIgnore?: boolean): Promise<AppUpdateInfo> {
    // Return cached result if within TTL (cache is skipped when bypassIgnore is set)
    if (!bypassIgnore) {
      const cached = await _readUpdateCache<AppUpdateInfo>(UPDATE_APP_CACHE_KEY)
      if (cached) return cached
    }

    const config = getConfig()
    const params: Record<string, string> = {
      appKey:             config.appKey,
      platform:           Platform.OS === 'android' ? 'ANDROID' : 'IOS',
      currentVersionCode: String(getAppVersionCode()),
    }
    const userId = getUserId()?.trim()
    if (userId) params.userId = userId
    if (bypassIgnore) params.bypassIgnore = 'true'

    const result = await apiRequest<AppUpdateInfo>('/api/v1/updates/app/check', {
      skipAuth: true,
      params,
    })
    const normalized = { ...result, downloadUrl: normalizeDownloadUrl(result.downloadUrl) }
    await _writeUpdateCache(UPDATE_APP_CACHE_KEY, normalized)
    return normalized
  },

  async openStore(appStoreUrl?: string, marketUrl?: string): Promise<void> {
    const url = Platform.OS === 'ios' ? appStoreUrl : marketUrl
    if (url) await Linking.openURL(url)
  },

  /**
   * 下载 APK 文件，返回 ArrayBuffer。
   * 支持进度回调（UpdateDownloadProgress），向下兼容（options 可选）。
   */
  async downloadApk(
    updateInfo: AppUpdateInfo,
    options?: {
      onProgress?: (progress: UpdateDownloadProgress) => void
    },
  ): Promise<ArrayBuffer> {
    const url = updateInfo.downloadUrl
    if (!url) throw new Error('[UpdateSDK] downloadApk: no downloadUrl in updateInfo')

    if (!options?.onProgress) {
      return _downloadBinary(url)
    }

    // Streaming download with detailed progress
    const response = await fetch(url)
    if (!response.ok) throw new Error(`[UpdateSDK] downloadApk failed: ${response.status}`)
    const contentLength = Number(response.headers.get('Content-Length') ?? '0')
    const reader = response.body?.getReader()
    if (!reader) return response.arrayBuffer()

    const chunks: Uint8Array[] = []
    let received = 0
    for (;;) {
      const { done, value } = await reader.read()
      if (done) break
      chunks.push(value)
      received += value.length
      options.onProgress({
        bytesDownloaded: received,
        totalBytes: contentLength,
        percent: contentLength > 0 ? Math.min(100, Math.round((received / contentLength) * 100)) : 0,
      })
    }
    const totalLength = chunks.reduce((acc, c) => acc + c.length, 0)
    const combined = new Uint8Array(totalLength)
    let offset = 0
    for (const chunk of chunks) {
      combined.set(chunk, offset)
      offset += chunk.length
    }
    return combined.buffer
  },

  /**
   * 下载插件 bundle，返回 bundle 文本内容（JS 源码）。
   * 支持进度回调（UpdateDownloadProgress），向下兼容（options 可选）。
   */
  async downloadPlugin(
    moduleId: string,
    updateInfo: PluginUpdateInfo,
    options?: {
      onProgress?: (progress: UpdateDownloadProgress) => void
    },
  ): Promise<string> {
    if (!updateInfo.downloadUrl) {
      throw new Error(`[UpdateSDK] downloadPlugin(${moduleId}): no downloadUrl in updateInfo`)
    }

    if (!options?.onProgress) {
      return _downloadText(updateInfo.downloadUrl)
    }

    // Streaming download with detailed progress
    const response = await fetch(updateInfo.downloadUrl)
    if (!response.ok) throw new Error(`[UpdateSDK] downloadPlugin failed: ${response.status}`)
    const contentLength = Number(response.headers.get('Content-Length') ?? '0')
    const reader = response.body?.getReader()
    if (!reader) return response.text()

    const chunks: Uint8Array[] = []
    let received = 0
    for (;;) {
      const { done, value } = await reader.read()
      if (done) break
      chunks.push(value)
      received += value.length
      options.onProgress({
        bytesDownloaded: received,
        totalBytes: contentLength,
        percent: contentLength > 0 ? Math.min(100, Math.round((received / contentLength) * 100)) : 0,
      })
    }
    const decoder = new TextDecoder()
    return chunks.map(c => decoder.decode(c, { stream: true })).join('') + decoder.decode()
  },

  /**
   * Android APK 直接下载并调起系统安装器。
   *
   * 当前实现使用 Linking.openURL 打开下载链接，由浏览器完成下载和安装引导。
   * 如需应用内下载 + 静默安装，宿主可集成 react-native-blob-util 并自行实现。
   */
  async downloadAndInstallApk(
    downloadUrl: string,
    options?: {
      onProgress?: (progress: number) => void
      sha256?: string
    },
  ): Promise<void> {
    if (Platform.OS !== 'android') throw new Error('[UpdateSDK] APK install is Android-only.')
    await Linking.openURL(downloadUrl)
  },

  // ── 插件（Bundle）热更新 ──────────────────────────────────────────────────

  /**
   * 检查指定插件的更新。
   *
   * 版本号由 SDK 自动从本地 AsyncStorage 缓存读取（首次为 0.0.0）。
   * 插件必须先通过 registerPlugin / registerPlugins 注册。
   */
  async checkPluginUpdate(moduleId: string): Promise<PluginUpdateInfo> {
    if (!_pluginRegistry.has(moduleId)) {
      throw new Error(
        `[UpdateSDK] Plugin "${moduleId}" not registered. ` +
        'Call UpdateSDK.registerPlugins([{ moduleId }]) first.',
      )
    }

    // Return cached result if within TTL
    const cacheKey = `${UPDATE_PLUGIN_CACHE_KEY_PREFIX}${moduleId}`
    const cached = await _readUpdateCache<PluginUpdateInfo>(cacheKey)
    if (cached) return cached

    const config = getConfig()
    const currentVersion = await _getCachedVersion(moduleId)
    const userId = getUserId()?.trim()
    const params: Record<string, string> = {
      appKey:         config.appKey,
      moduleId,
      platform:       Platform.OS === 'android' ? 'ANDROID' : 'IOS',
      currentVersion,
    }
    if (userId) params.userId = userId

    const result = await apiRequest<PluginUpdateInfo>('/api/v1/rn/update/check', {
      skipAuth: true,
      params,
    })
    const normalized = {
      ...result,
      currentVersion,
      downloadUrl: normalizeDownloadUrl(result.downloadUrl) ?? result.downloadUrl,
    }
    await _writeUpdateCache(cacheKey, normalized)
    return normalized
  },

  /**
   * 执行插件更新（一步完成）。
   *
   * SDK 内部自动：检查版本 → 下载 bundle → 写入文件系统 → 触发重载（silent = false 时）。
   *
   * 需先调用 setBundleCallbacks 注入写入/重载能力。
   *
   * @param silent true = 静默更新，下次启动生效；false（默认）= 立即重载
   */
  async updatePlugin(
    moduleId: string,
    options?: {
      onProgress?: (progress: number) => void
      silent?: boolean
    },
  ): Promise<void> {
    const info = await UpdateSDK.checkPluginUpdate(moduleId)
    if (!info.needsUpdate) return

    const source = await _downloadText(info.downloadUrl, options?.onProgress)

    // MD5 校验
    if (info.md5) {
      const actual = md5(source)
      if (actual !== info.md5) {
        throw new Error(
          `[UpdateSDK] Bundle MD5 mismatch for "${moduleId}": expected ${info.md5}, got ${actual}`,
        )
      }
    }

    // 写入 AsyncStorage 缓存（版本记录）
    const cachePayload: CachedRnBundle = {
      moduleId,
      version:      info.latestVersion,
      md5:          info.md5,
      source,
      downloadedAt: new Date().toISOString(),
    }
    await AsyncStorage.setItem(bundleCacheKey(moduleId), JSON.stringify(cachePayload))

    // 写入宿主文件系统（需注入 setBundleCallbacks）
    if (_writeBundleCallback) {
      await _writeBundleCallback(moduleId, source)
    }

    // 触发重载（非静默模式）
    if (!options?.silent && _reloadBundleCallback) {
      await _reloadBundleCallback(moduleId)
    }
  },

  // ── 版本信息 ──────────────────────────────────────────────────────────────

  getAppVersionCode,
  getAppVersionName,

  _devSetAppVersion(versionCode: number, versionName?: string): void {
    _devSetAppVersion(versionCode, versionName)
  },
}